Such travel can be understood as well horizontally as vertically. Thus, the missile according to the invention can be applied in submarine horizontal movement, for example for heavy transportation over long distances, such as submarine tanks. Otherwise, it can be used in vertical submarine movement, for example by sending ground receiver or penetrometers or the imersion and the hiding in the ground of industrial wastes. This missile can also be used in the design of air transportation vehicles such as airships, or missiles the path of which is approximately vertical such as rockets or similar devices.
The objective for such missiles is essentially the obtaining of high velocities, much higher to those of known devices for the same applications at a comparable weight, dimension and power. In addition, the missiles according to the invention have additional properties, such as stability, manuverability and absence of noise.
It is well known that, for such devices which are intended to move in a fluid, the shape of the front portion and of the rear portion are determined by technological considerations limited to the applications for which these missiles are designed. Thus, the front part can be pointed for the penetration, or round to shield receiver equipment (antennas, etc.) while the rearward shape is prescribed by considerations of motorization and stability involving optionally small wings, propellers, and systems for unwinding cables, etc.
On the other hand, most frequently, for reasons of simplicity, the front portion and the rear portion are united by a central cylindrical portion. The consequence of this configuration is to involve a high coefficient of drag (Cx) about 0.20, and detachement of the boundary layer which brings about instabilities, loss of action of the control surfaces, existence of cavitation phenomena involving lowering of the performance and increased noise.
This invention consists in substituting this cylindrical portion with a joining portion which profile is designed so that the pressure coefficient is in accordance with the most adapted law, according to the specificities of the missile. According to a preferred embodiment of the invention, for which the present specification is written, the profile is designed so that the pressure coefficient is practically constant over the length of this profile.
For this purpose, the invention consists in determining and following a profile, so that for the front portion of a given shape, the natural wake lines of the foresaid front portion form the front profile which is joined to the imposed rear portion, in such a manner that the coefficient of pressure remains constant at all points of the joining portion.
It should be observed that studies covering the design of profiles having approximatively constant pressure coefficient over an imposed section were previously made.
Thus, Ira H. ABBOTT, the NASA Director, ("Theory of Wing Sections", Dover Public inc., NY, 1949, pages 73 and 328) disclosed a method of optimization of a thin profile portion in order to obtain an ideal lift coefficient over this portion. But this method is based on a linear distribution of singularities like vortex, i.e. on the linearized theory of wings, referred, due to the linearization, to their mean lines, equidistant from the upper surfaces and the lower surfaces of the profile.
Then, these profiles are calculable by the well known theory of the functions of the compound variable and particularly by mean of the conformal mapping, as described by GORNSTEIN in U.S. Pat. No. 3,946,688.
However, such a method can only be applied to thin profiles and plan flows, and not axisymetrical profiles. Indeed, the thin circular stripes of the vortex over an axisymetrical body can not be reduced according to this theory in an element, the measurement of which is zero. Should someone wish to extrapolate, it should be necessary to use an uniform distribution of the normal doublets on the centered disks, which would not permit factoring in the previously cited constraints for the missiles according to the invention, namely
the previously defined shape of the front and rear portions, and, PA1 a constant pressure on the portion joining the front and the rear portions. PA1 the hypotheses of linearization of ABBOTT, PA1 the possibilities of the analysis as taken from GORNSTEIN, PA1 and the criterions of optimization based on the lift properties, free of any meaning for an axisymetrical body.